Ore slurry handling apparatus



June 4, 1968 L cs. WOQD ORE SLURRY HANDLING APPARATUS 2 Sheets-Sheet 1 Filed April 25, 1966 INVENTOR LONNIE G. WOOD ATTOR EY June 4, 1968 L. G. WOOD 3,366,669

ORE SLURRY HANDLING APPARATUS Filed April 25', 1966 2 Shgets-Sheec 2 INVENTOR LONNIE 6. W000 BY ATTORNEY.

United States Patent 3,386,669 ORE SLURRY HANDLING APPARATUS Lonnie G. Wood, Lakeland, Fla., assignor to The Borden Company, New York, N.Y., a corporation of New Jersey Filed Apr. 25, 1966, Ser. No. 545,152 9 Claims. (Cl. 241-4613) This invention relates to ore slurry handling apparatus, and more particularly concerns apparatus for reducing and limiting the particle size of ore slurry flowing in a sump to a pump inlet therein.

In those mining operations in which ore is reduced to a slurry in a sump and then pumped to a processing plant, it is necessary to limit the size of the solid particles entering the pump inlet to protect the pump from damage. To this end, a grizzly is commonly positioned in the flow path of the slurry so as to prevent oversize particles from entering the pump inlet. However, this arrangement presents another problem in that the grizzly becomes clogged with oversize particles from time to time, reducing the flow of slurry to the pump inlet and causing cavitation of the pump, with the result that pumping efficiency is reduced and damage to the pump or the pipe line may occur.

Accordingly, one of the objects of the present invention is to provide an improved grizzly structure for ore slurry sumps capable of minimizing cavitation of the pump which conveys slurry from the sump.

Another object of the present invention is to provide a grizzly structure for ore slurry sumps which contributes to improved ore slurry pumping rates and minimizes loss of production time.

Further objects and advantages of the invention will become apparent as the following description proceeds, and the features of novelty which characterize the inven tion will be pointed out with particularity in the claims forming the concluding portion of this specification.

Briefly stated, in accordance with one aspect of the invention, there is provided a grizzly structure for ore slurry sumps so arranged that it may pivot about its lower edge and cooperate with a stationary breaker plate adjacent the lower portion thereof so as to perform a particle crushing function when pivoted into crushing engagement with the breaker plate. Preferably, the lower portion of the grizzly and the breaker plate are provided with cooperating teeth for gripping and crushing obstructions therebetween, and a power operated device is utilized to pivot the grizzly toward the breaker plate whenever obstructions are encountered.

For a better understanding of the invention, reference may be made to the following description taken in connection with the accompanying drawings in which:

FIGURE 1 is a schematic elevational view, partially in section, of a typical mining operation utilizing the present invention;

FIGURE 2 is a perspective view of a grizzly structure embodying the present invention, portions being broken away to show details of construction;

FIGURE 3 is a schematic side view of the structure shown in FIGURE 2; and

FIGURE 4 is similar to FIGURE 3, but shows the parts in a different position.

Referring to the drawings, the numeral designates a dragline utilized to remove the ore or matrix 12 from an open pit 13 and to deposit it in a sump 14 nearby. Streams of water under high pressure are directed by one or more high pressure water guns 16 towards the matrix 12 as it accumulates in the sump 14 so as to form a slurry which may be pumped to an ore processing plant at another location. The mining of phosphate ore is carried on in this manner, although it is to be understood that the ice invention is not limited to this particular application. A pump 18 having a venturi inlet 20 submerged in the sump 14 is utilized to pump the slurry to the processing plant, and a water injector 22 cooperates with the venturi inlet 2%) to increase the pressure on the suction side of the pump, to provide dilution water and to make the pump self-priming. Preferably, operation of the pump 18 is regulated by a control system including a float 23 which rises and falls with the level of the slurry in the sump 14 so as to prevent pumping whenever the slurry level drops below the pump inlet 20.

The pump inlet 20 is enclosed by a rectangular cage structure 24 resting on the bottom of the sump 14. The cage structure 24 comprises a base 26 including a pair of runners 28 to facilitate movement from one sump to another, vertical support members 30 on which are mounted top frame members 32 and suitably spaced vertical grid bars 34- on the two sides and the rear of the cage structure. Enclosing the opening on the front or fourth side of the cage structure 24 is a grizzly 36 having grid bars 38 spaced to define openings of a size appropriate to bar the entrance of oversize particles of solid matter which might damage the pump 18. In accordance with the present invention, the grizzly 36 performs a crushing function as well as a screening function, and for this purpose is pivoted along its lower edge on the base 26 by means of a pivot pin 4t). Spaced crushing teeth 42 are provided on the lower portion of the grizzly 36, and these are arranged to cooperate with a stationary breaker plate 44 rigidly supported on the base 26 in front of and inclined at an angle from the grizzly 36. Crushing teeth 46 are also provided on the breaker plate 44, and preferably each is offset laterally with respect to its neighboring tooth 42 on the grizzly 36 to improve crushing action.

Movement of the grizzly 36 about its pivotal axis between its upright position and a forwardly inclined position, in which the teeth 42 and the teeth 46 are brought into crushing cooperation, is effected by a suitable force applying device, such as the hydraulic ram 48. The ram 48 is mounted at one end on a fixed lug 50 secured to one of the top frame members 32, and at the other end on a lug 52 on the upper edge of the grizzly 36. Thus, hydraulic pressure may be utilized to drive the grizzly 36 forwardly to its crushing position and to return it to its vertical normal position.

In order to prevent mud balls and the like from obstructing the openings between the grid bars 38 of the grizzly 36, a group of spaced water jet nozzles 54 mounted on a pair of conduits 56 extending transversely along the rear of the grizzly 36 are aimed toward the openings therein. Water under high pressure supplied to the conduits 56 is directed by the nozzles 54 between the grid bars 38, thus providing a flushing action which aids in preventing clogging of the grizzly 36.

It is necessary to prevent the slurry and any oversize particles or calls therein in the sump 14 from flowing under the breaker plate 44 and thence into the pump inlet 2%), and for this purpose a retaining plate 58 is mounted on the lower edge of the breaker plate 44. Preferably, the retaining plate 58 is mounted on a hinge pin 60 so that it is free to pivot and rest in contact with the bottom of the sump 14. Alternatively, the rectangular cage structure 24 can be provided with vertical grid bars across the base 26 to prevent such particles from getting into the pump inlet 20.

The operation of the embodiment of the invention which has been described should now be apparent. After the matrix 12 deposited in the sump 14 has been reduced to a slurry, some particles or balls of matrix remain too large to pass through the openings between the grid bars 33 of the grizzly 36. As the slurry is pumped from the sump 14 by the pump 18, these oversize balls or particles are trapped along the lower front surface of the grizzly 36, and in time may reduce the flow of slurry to such an extent that cavitation of the pump 13 results. To avoid this undesirable result, the grizzly 36 is pivoted forwardly by actuating the hydraulic ram 48 whenever oversize particles block the openings between the grid bars 33, and the particles are crushed between the teeth 42 on the lower portion of the grizzly 36 and the teeth 46 on the stationary breaker plate 44-. After each crushing operation the grizzly 36 is, of course, returned to its vertical position by the hydraulic ram 48. Further, mud balls and the like which accumulate in the spaces between the grid bars 33 are removed from time to time by supplying water under high pressure to the water jet nozzles 54, thus directing streams of water through the openings in the grizzly 36.

While I have shown and described a particular embodiment of my invention, 1 do not desire the invention to be limited to the particular construction disclosed, and I intend by the appended claims to cover all modifications with the true spirit and scope of my invention.

I claim:

1. Apparatus for reducing and limiting the particle size of ore slurry flowing in a sump to a pump inlet therein comprising a grizzly adapted to be positioned in the flow path of the slurry, a base for supporting said grizzly, the lower edge of said grizzly being pivotally mounted on said base, a breaker plate fixedly secured to said base facing said grizzly and extending upwardly at an angle therefrom, crushing means on the lower portion of said grizzly facing said breaker plate, and reciprocating means for pivoting said grizzly and thereby moving said crushing means into crushing cooperation with said breaker plate so as to crush oversize ore particles trapped therebetween.

2. Apparatus as set forth in claim 1 including means for directing jets of water through the openings in said grizzly.

3. Apparatus as set forth in claim 1 in which said breaker plate includes a plurality of spaced crushing teeth on the surface thereof facing said grizzly, and the crushing means on said grizzly includes a plurality of spaced crushing teeth laterally offset with respect to the crushing teeth on said breaker plate.

4. Apparatus as set forth in claim 1 in which said reciprocating means includes a hydraulic ram.

5. Apparatus as set forth in claim 1 including means for directing jets of water through the openings in said grizzly and in which said breaker plate includes a plurality of spaced crushing teeth on the surface thereof facing said grizzly, the crushing means on said grizzly includes a plurality of spaced crushing teeth laterally offset with respect to the crushing teeth on said breaker plate, and said reciprocating means includes a hydraulic ram.

6. Apparatus for reducing and limiting the particle size of ore slurry flowing in a sump to a pump inlet therein comprising a base, a plurality of upright grid bars supported by said base and arrayed to form three sides of a rectangular enclosure for said pump inlet, a grizzly pivotally supported along its lower edge on said base so as to form a fourth side of said enclosure, a breaker plate secured to said base facing the lower portion of said grizzly, said breaker plate extending upwardly at an angle from the lower edge of said grizzly and having first crushing means thereon, second crushing means on the lower portion of said grizzly arranged to cooperate with said first crushing means, and reciprocating means for pivoting said grizzly toward said breaker plate to effect crushing of oversize ore particles trapped therebetween.

7. Apparatus as set forth in claim 6 including means for directing jets of water through the openings in said grizzly.

3. Apparatus as set forth in claim 6 in which said breaker plate includes a plurality of spaced crushing teeth on the surface thereof facing said grizzly, and the crushing means on said grizzly includes a plurality of spaced crushing teeth laterally offset with respect to the crushing teeth on said breaker plate.

9. Apparatus as set forth in claim 6 in which said re ciprocating means includes a hydraulic ram.

References Cited UNITED STATES PATENTS 2,318,142 5/1943 Cox et a1 24l95 XR 2,581,501 1/1952 Shaver 24l95 XR 2,772,053 11/1956 Schmidtmann 241-94 3,105,643 10/1963 Todd 241-95 3,223,334 12/1965 Wuthrich 241-84 RX WILLIAM W. DYER, JR., Primary Examiner.

' W. D. BRAY, Assistant Examiner. 

1. APPARATUS FOR REDUCING AND LIMITING THE PARTICLE SIZE OF ORE SLURRY FLOWING IN A SUMP TO A PUMP INLET THEREIN COMPRISING A GRIZZLY ADAPTED TO BE POSITIONED IN THE FLOW PATH OF THE SLURRY, A BASE FOR SUPPORTING SAID GRIZZLY, THE LOWER EDGE OF SAID GRIZZLY BEING PIVOTALLY MOUNTED ON SAID BASE, A BREAKER PLATE FIXEDLY SECURED TO SAID BASE FACING SAID GRIZZLY AND EXTENDING UPWARDLY AT AN ANGLE THEREFROM, CRUSHING MEANS ON THE LOWER PORTION OF SAID GRIZZLY FACING SAID BREAKER PLATE, AND RECIPROCATING MEANS FOR PIVOTING SAID GRIZZLY AND THEREBY MOVING SAID CRUSHING MEANS INTO CRUSHING COOPERATION WITH SAID BREAKER PLATE SO AS TO CRUSH OVERSIZE ORE PARTICLES TRAPPED THEREBETWEEN. 